import tkinter
from tkinter import ttk
class MainWindow():
    def __init__(self):
        self.root = tkinter.Tk()
        self.root.minsize(370,500)
        self.root.geometry('250x500+0+0')
    def add_frame(self):
        frame = ttk.Frame(self.root)
        frame.grid(column=1, row=1)
        username = tkinter.StringVar()
        name = ttk.Entry(frame, textvariable=username)
        name.grid(column=100, row=99, columnspan=400, sticky=(tkinter.W,tkinter.E))
        btn_c = ttk.Button(frame, text='C')
        btn_c.grid(column=100, row=100, columnspan=200, sticky=(tkinter.W,tkinter.E))
        btn_re = ttk.Button(frame, text='%')
        btn_re.grid(column=300, row=100)
        btn_division = ttk.Button(frame, text='/')
        btn_division.grid(column=400, row=100)
        btn_7 = ttk.Button(frame, text='7')
        btn_7.grid(column=100, row=200)
        btn_8 = ttk.Button(frame, text='8')
        btn_8.grid(column=200, row=200)
        btn_9 = ttk.Button(frame,text='9')
        btn_9.grid(column=300,row=200)
        btn_multiplication = ttk.Button(frame, text='*')
        btn_multiplication.grid(column=400, row=200)
        btn_4 = ttk.Button(frame, text='4')
        btn_4.grid(column=100,row=300)
        btn_5= ttk.Button(frame, text='5')
        btn_5.grid(column=200, row=300)
        btn_6 = ttk.Button(frame, text='6')
        btn_6.grid(column=300, row=300)
        btn_ubtraction = ttk.Button(frame, text='-')
        btn_ubtraction.grid(column=400, row=300)
        btn_1 = ttk.Button(frame, text='1')
        btn_1.grid(column=100, row=400)
        btn_2 = ttk.Button(frame, text='2')
        btn_2.grid(column=200, row=400)
        btn_3 = ttk.Button(frame, text='3')
        btn_3.grid(column=300, row=400)
        btn_add = ttk.Button(frame, text='+')
        btn_add.grid(column=400, row=400)
        btn_0 = ttk.Button(frame, text='0')
        btn_0.grid(column=100, row=500, columnspan=200, sticky=(tkinter.W, tkinter.E))
        btn_decimal_point = ttk.Button(frame, text='.')
        btn_decimal_point.grid(column=300, row=500)
        btn_equal= ttk.Button(frame, text='=')
        btn_equal.grid(column=400, row=500)
    def show(self):
        self.root.mainloop()

mw = MainWindow()
mw.add_frame()
mw.show()